South Korea plans an unprecedented peace-time mobilization of soldiers and police to minimize any trouble when it plays host to the leaders of the world's top 20 economies next month. South Korea's military, coast guard and police said they are preparing for all imaginable disruptions during next month's G-20 Summit in Seoul.

Those include large demonstrations, riots, terror and cyber-attacks, and attempts by rival North Korea to spoil the meeting.

The commissioner general of the South Korean National Police Agency, Cho Hyun-Oh, noted Monday that some previous G-20 and other major international summits have been plagued with violence. Combining that with the aggressive reputation of South Korean demonstrators, he said, means authorities must be prepared for the worst during next month's event.

Cho predicts that protests during the G-20 Seoul Summit, though, will not be very violent, and his forces will be able to prevent the situation from getting out of hand. He is mobilizing 50,000 police officers - more than one-third of the national force - to provide security in Seoul during the summit November 11th and 12th.

South Korea's Joint Chiefs of Staff say the armed forces will go on a "Level 3" alert, which is the highest, starting at the end of this month.

The Defense Ministry is preparing for eight possible types of provocative acts by North Korea, including intrusions south of the Northern Limit Line, the disputed maritime border in the Yellow Sea. The Coast Guard will defend the Han River in Seoul. And the Air Force will be on the lookout for planes that may try to intrude into the airspace over the summit. Cho said he expects the military will be prepared to use anti-aircraft missiles in the capital should any invasions of airspace occur.

The fifth G-20 summit is expected to be the largest so far - attracting 10,000 participants, including 32 heads of government and leaders of international organizations.

The leaders attending include U.S. President Obama, Chinese President Hu Jintao, and the heads of several European countries. In addition, U.N. Secretary-General Ban Ki-moon and the heads of the International Monetary Fund and World Bank will be there.

South Korean officials say they have ample experience in holding such an event, noting the successful 2002 World Cup and the 2005 APEC summit. Even so, they say severe traffic congestion can be expected throughout the capital during the G-20 Summit.